Climate change triggers severe coral loss, threatening ecosystems worldwide
Over a single decade, the world has lost 14% of its coral reefs due to rising ocean temperatures, pollution, and destructive fishing practices, according to the most comprehensive coral health survey to date. These vibrant ecosystems, essential to marine biodiversity, have been transformed into bleached, lifeless skeletons.
The Global Coral Reef Monitoring Network’s findings highlight that regions such as South Asia, the Pacific, the Arabian Peninsula, and Australia’s coastlines were hit hardest. Paul Hardisty, CEO of the Australian Institute of Marine Science, emphasised that climate change poses the greatest danger, as oceans absorb over 90% of excess heat from greenhouse gas emissions. This leads to prolonged marine heatwaves, pushing coral species beyond their survival thresholds.
Bleaching events, like the one in 1998 that eradicated 8% of global corals, are stark reminders of these dangers. Coral reefs, though occupying just 0.2% of the ocean floor, support over 25% of marine life and provide essential benefits to millions of people. They generate approximately US$2.7 trillion annually in goods and services, including US$36 billion from tourism.
Widespread Losses with Regional Variations
Between 2009 and 2018, coral loss varied dramatically. While East Asia saw a relatively modest 5% decline, the eastern tropical Pacific suffered catastrophic losses of up to 95%. The report also notes that the total coral lost globally since 2009 exceeds all living coral in Australia.
The UN Environment Programme’s Inger Andersen stressed the urgency of action: “We can reverse these losses, but we must act now.” Projections from the Intergovernmental Panel on Climate Change (IPCC) warn that 70–90% of corals will vanish at 1.5°C of global warming, and nearly all will disappear at 2°C.
Signs of Hope and Resilience
Despite the alarming trends, there is cautious optimism. Some reefs, particularly in East and Southeast Asia’s “Coral Triangle,” which houses 30% of the world’s reefs, demonstrated resilience and recovery. Unique species in the region may offer insights into restoring degraded reefs globally.
Drawing on 40 years of data across 12,000 sites in 73 countries, the survey measured coral health by comparing areas of healthy coral with those overtaken by algae, a key distress indicator. Supported by UNEP and the International Coral Reef Initiative, the findings underscore the urgent need to protect and regenerate these critical ecosystems before it’s too late.
